Grommet

ABSTRACT

A grommet that can achieve both an improvement of visibility of a locking portion at the start of attachment of the grommet and a reduction of an insertion force that is required during the attaching operation, and that thus has excellent ease of attachment is provided. A grommet includes a truncated cone-shaped portion having a larger diameter than an attachment hole, an annular seal lip portion on an attachment surface side that opposes a panel member, a first locking portion that protrudes from the attachment surface on an inward side with respect to a radial direction of the annular seal lip portion, and that is to be locked on the panel member, and a second locking portion that protrudes from the attachment surface on the inward side with respect to the radial direction of the annular seal lip portion, and that is to be locked on the panel member.

TECHNICAL FIELD

The present invention relates to a grommet and particularly relates to agrommet that, when mounted onto an attachment hole that is formed in apanel member such as a vehicle body panel or the like, protects a wireharness and the like inserted into that attachment hole and seals theattachment hole in a water-tight manner.

BACKGROUND ART

Generally, a panel member such as a vehicle body panel or the like has aplurality of openings into which wiring and piping are inserted. Anopening into which a wire harness or the like is inserted constitutes anattachment hole to which a grommet for protecting the wire harness andfor waterproofing is attached.

As a conventional grommet of this type, as shown in FIG. 5, for example,a grommet is known in which a coupling flange 112 of an insertion tubeportion 104 into which a wire harness (wire group) W is inserted isfitted into a space behind a waterproof lip 106 of a grommet mainportion 102, and a seal ring 118 is placed in the vicinity of a frontlocking claw 105A and a rear locking claw 105B on a leading end side ofthe insertion tube portion 104 (see Patent Document 1, for example).

With this grommet, in a state in which the front locking claw 105A isengaged with a back surface side of a through hole 108, a couplingportion 113 of the grommet main portion 102 is pushed toward the throughhole 108, thereby engaging the rear locking claw 105B with an outercircumferential portion of the through hole 108. This is advantageous inthat the operation for attaching the grommet can be facilitated whencompared with the case where the grommet is fitted linearly into thethrough hole 108 by pushing the grommet main portion 102 and theinsertion tube portion 104 into the through hole 108 while aligning thecenter of the insertion tube portion 104 with the center of the throughhole 108.

CITATION LIST Patent Documents

Patent Document 1: JP H08-007688A

SUMMARY OF INVENTION Technical Problem

However, in the above-described conventional grommet, the front lockingclaw 105A and the rear locking claw 105B are provided radially inward ofthe waterproof lip 106, and furthermore, a circumferential end surfaceof the coupling portion 113 is disposed radially outward of thewaterproof lip 106 and on a side that is closer to a worker. Therefore,during the operation for attaching the grommet, the front locking claw105A, the seal ring 118, and the like are hardly visible, and thus theoperation for attaching the grommet cannot be sufficiently facilitated.

To address this issue, it is possible to improve the visibility of thevicinity of the through hole 108 by reducing the diameters of thecoupling flange 112 of the insertion tube portion 104 and the couplingportion 113 of the grommet main portion 102. However, in that case, themore the visibility of the front locking claw 105A and the like isincreased by reducing the diameter of the coupling portion 113 of thegrommet main portion 102, the larger the force that is required to pushthe coupling portion 113 toward the through hole 108, that is, aninsertion force that is required to attach the grommet. For this reason,the operation for attaching the grommet still cannot be sufficientlyfacilitated.

Thus, it is an object of the present invention to provide a grommet thatcan achieve both an improvement of the visibility of a locking portionat the start of attachment of the grommet and a reduction of theinsertion force that is required during the attaching operation, andthat thus has excellent ease of attachment.

Solution to Problem

To achieve the above-described object, a grommet according to thepresent invention is a grommet including a tubular grommet main bodythat has a truncated cone-shaped portion having a larger diameter thanan attachment hole of a panel member and that has an annular seal lipportion on an attachment surface side of the truncated cone-shapedportion that opposes the panel member, a first locking portion thatprotrudes from the attachment surface of the truncated cone-shapedportion on an inward side with respect to a radial direction of theannular seal lip portion, and that is to be locked on the panel memberthrough the attachment hole, and a second locking portion that protrudesfrom the attachment surface of the truncated cone-shaped portion on theinward side with respect to the radial direction of the annular seal lipportion, and that is to be locked on the panel member through theattachment hole when the annular seal lip portion of the grommet mainbody comes into contact with the panel member. The grommet is configuredsuch that the first locking portion has a base end portion thatprotrudes from the attachment surface of the grommet main body on theinward side with respect to the radial direction of the annular seal lipportion, and a leading end portion that protrudes from the base endportion toward the truncated cone-shaped portion on an outward side withrespect to the radial direction of the annular seal lip portion, and thesecond locking portion is disposed on a side that is opposite to thefirst locking portion with respect to at least the center of thetruncated cone-shaped portion of the grommet main body.

With this configuration, the leading end portion of the first lockingportion of the grommet according to the present invention is located onthe outward side with respect to the radial direction of the annularseal lip portion, and thus the visibility of the first locking portionat the start of attachment of the grommet can be improved. Moreover, itis possible that during attachment of the grommet according to thepresent invention to the panel member, the first locking portion isinserted into the attachment hole first, the grommet is rotated usingthat first locking portion as the fulcrum, and the second lockingportion that is disposed on the side opposite to the first lockingportion is locked on the panel member. As a result, a long distancebetween the leading end portion of the first locking portion, whichserves as the fulcrum, and the second locking portion, which serves asthe point of application of force, can be secured, because the leadingend portion of the first locking portion is located on the outward sidewith respect to the radial direction of the annular seal lip portion.Thus, the grommet can be easily inserted into the attachment hole usingthe principle of levers. Accordingly, the insertion force that isrequired during the attaching operation can be reduced.

Therefore, the grommet according to the present invention can provide agrommet that can achieve both an improvement of the visibility of thelocking portion at the start of attachment of the grommet and areduction of the insertion force that is required during the attachingoperation, and that thus has excellent ease of attachment.

Moreover, in the grommet having the above-described configuration, thegrommet main body may have a tubular insertion wail portion that is tobe inserted into the attachment hole of the panel member, and the firstlocking portion and the second locking portion may be formed integrallywith the insertion wall portion.

With this configuration, in the grommet according to the presentinvention, the first locking portion and the second locking portion canbe formed integrally with the insertion wall portion, so that thestrength of the grommet can be secured while reducing the manufacturingcost of the grommet.

Moreover, in the grommet having the above-described configuration, theinsertion wall portion may be composed of a hard material having aflange portion that is embedded in the truncated cone-shaped portion,and at least the annular seal lip portion may be composed of an elasticmaterial that is softer than the hard material.

With this configuration, in the grommet according to the presentinvention, the first locking portion, the second locking portion, andthe like, which are integral with the insertion wall portion, and theflange portion can be composed of a hard material. Moreover, when thegrommet is mounted onto the attachment hole, and the annular seal lipportion abuts against the panel member on the outside of the attachmenthole, the seal lip portion composed of an elastic material that issofter than the insertion wall portion can be supported by the flangeportion, and thus the sealability can be secured.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a grommetthat can achieve both the improvement of the visibility of a lockingportion at the start of attachment of the grommet and the reduction ofthe insertion force that is required during the attaching operation, andthat thus has excellent ease of attachment.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing a state in which a grommetaccording to a first embodiment of the present invention is fitted to apanel member.

FIG. 2 is a cross-sectional view showing a state before the grommetaccording to the first embodiment of the present invention is fitted tothe panel member.

FIG. 3 is a perspective view showing the state in which the grommetaccording to the first embodiment of the present invention is fitted tothe panel member.

FIG. 4 is a cross-sectional view showing a state in which the grommetaccording to the present embodiment is fitted to another panel member.

FIG. 5 is a cross-sectional view showing a conventional grommet.

DESCRIPTION OF EMBODIMENTS

Next, an embodiment of the present invention will be described withreference to the drawings.

The configuration will be described first. FIGS. 1 to 3 show a grommetaccording to the present embodiment.

As shown in FIGS. 1 to 3, a grommet 1 is constituted by a wire groupinsertion member 2 that is composed of a hard material such aspolypropylene, for example, and a seal member 3 that is composed of anelastic material that is softer than the wire group insertion member 2,such as synthetic rubber (silicone rubber) or an elastomer for example.The grommet 1 is attached to an attachment hole H of a panel member P.

The panel member P may be a vehicle body panel or the like and has theattachment hole H into which a wire group W is inserted via the grommet1. The attachment hole H is a through hole that is formed in the panelmember P and that has a perfect circular shape, an elliptical or ovalshape, or a rectangular shape. Preferably, the attachment hole H is athrough hole having an elliptical or oval shape or a rectangular shapethat is elongated in the vertical direction in FIG. 1. The attachmenthole H is configured such that attaching the grommet 1 between the wiregroup W and the attachment hole H secures a tight enough seal to preventintrusion of foreign matter such as water.

The wire group insertion member 2 has an insertion wall portion 21, aflange portion 22, a first insertion portion 23, a second insertionportion 24, a first locking portion 25, and second locking portions 26,the various portions being integrated into a single body.

In the present embodiment, as shown in FIG. 3, the insertion wallportion 21 is formed into a tubular shape having substantially the sameshape as the opening edge shape of the attachment hole H that has asubstantially elliptical shape. Moreover, the insertion wall portion 21is configured to be located on an inner circumference of the attachmenthole H when the grommet 1 is attached to the panel member P.

The flange portion 22 is disposed between the first insertion portion 23and the insertion wall portion 21 in such a manner as to be embedded ina truncated cone-shaped portion 32, which will be described later. Theflange portion 22 has an increased diameter such that its outercircumferential edge is located radially outward of the attachment holeH, and is configured to oppose the panel member P when the grommet 1 isattached to the panel member P.

The first insertion portion 23 is disposed radially inward of the flangeportion 22 and closer to the seal member than the insertion wall portion21 is. The first insertion portion 23 is configured to have asubstantially cylindrical shape, and the wire group W from the inside ofthe seal member 3 is directly inserted into the first insertion portion23.

The second insertion portion 24 is disposed on a side of the insertionwall portion 21 that is opposite to the first insertion portion 23, andhas a tubular shape that is bent so as to extend parallel to the panelmember P. Thus, the wire group W from the insertion wall portion 21 isinserted into the second insertion portion 24 in a bent state.

The first locking portion 25 has a base end portion 25A and a leadingend portion 25B that are integrated into a single body. The base endportion 25A shares the insertion wall portion 21 in a lower portion ofthe drawings and therefore protrudes from an attachment surface 32 a onan inward side with respect to a radial direction of an annular seal lipportion 33, which will be described later. In addition to sharing theinsertion wall portion 21, the base end portion 25A extends parallel tothe panel member P and outwardly with respect to the radial direction ofthe annular seal lip portion 33. The leading end portion 25B protrudesfrom an end of the base end portion 25A toward the truncated cone-shapedportion 32, on an outward side with respect to the radial direction ofthe annular seal lip portion 33.

The second locking portions 26 are formed at a plurality of positions onthe insertion wall portion 21. The second locking portions 26 protrudefrom the attachment surface 32 a on the inward side with respect to theradial direction of the annular seal lip portion 33, and are locked onthe panel member P through the attachment hole H when the annular seallip portion 33 comes into contact with the panel member P. One of thesecond locking portions 26, that is, the second locking portion 26 in anupper portion of the drawings is disposed on a side opposite to thefirst locking portion 25 with respect to the center of the truncatedcone-shaped portion 32.

Each of the second locking portions 26 is formed by separating a portionof the insertion wall portion 21 from the insertion wall portion 21,with one end of that portion being left connected to the insertion wallportion 21, in such a manner as to be cut and raised from the insertionwall portion 21. An engagement claw 26 a is formed at the other end ofthe second locking portion 26, and the other end can be displaced towardthe inside of the insertion wall portion 21. Accordingly, when thegrommet 1 is mounted onto the panel member P, the second locking portion26 is pressed against an opening edge portion of the attachment hole Hand temporarily displaced to the inside of the insertion wall portion21. In a state in which the grommet 1 is attached to the panel member P,the other end of the second locking portion 26 is out of the attachmenthole H and is elastically restored, and the locking claw 26 a at the oneend is locked on the opening edge portion of the attachment hole H.

The seal member 3 is the member for securing the sealability between thewire group insertion member 2 and the panel member P. The seal member 3has a flange covering portion 31, the truncated cone-shaped portion 32,the annular seal lip portion 33, a wire group insertion port coveringportion 34, and a wire group sealing portion 35.

The flange covering portion 31 covers the flange portion 22 such thatthe flange portion 22 is embedded therein. Moreover, the annular seallip portion 33 is formed integrally with the flange covering portion 31on a side of the flange covering portion 31 that opposes the panelmember P.

The annular seal lip portion 33 is formed into a pleated shape,protruding annularly from the truncated cone-shaped portion 32 and theflange covering portion 31 so as to oppose the panel member P, andsecures the sealability of the outer circumference of the attachmenthole H by being pressed against the panel member P. The annular seal lipportion 33 is configured such that the pressing force applied to thepanel member P is not dissipated, because the flange portion 22 made ofa hard material is located between the annular seal lip portion 33 andthe flange covering portion 31.

The wire group insertion port covering portion 34 is formed into acylindrical shape that is continuous with the flange covering portion 31and covers the first insertion portion 23.

The wire group sealing portion 35 is a cylindrical tube member that isformed continuously with the wire group insertion port covering portion34, and secures the sealability by covering the wire group W. The wiregroup sealing portion 35 has a smaller diameter than the wire groupinsertion port covering portion 34 and covers the wire group W whilebeing in close contact therewith.

The truncated cone-shaped portion 32 is formed by covering the flangeportion 22 with the flange covering portion 31, and is configured tohave a larger diameter than the attachment hole H of the panel member P.

The wire group insertion port covering portion 34 and the wire groupsealing portion 35 are tubular members and have a communication hole 4inside, into which the wire group W is inserted. Moreover, the grommet 1has the insertion wall portion 21 that is inserted into the attachmenthole H of the panel member P, and the first locking portion 25 and thesecond locking portions 26 are formed integrally with the insertion wallportion 21.

It should be noted that the truncated cone-shaped portion 32 having alarger diameter than the attachment hole H of the panel member P, theannular seal lip portion 33 provided on the attachment surface 32 a sideof the truncated cone-shaped portion 32 that opposes the panel member P,and the tubular insertion wall portion 21 that is to be inserted intothe attachment hole H of the panel member P constitute a tubular grommetmain body according to the present invention.

Next, a method for mounting the grommet 1 according to the presentembodiment onto the panel member P will be described.

First, as shown in FIG. 2, during mounting of the grommet 1, the firstlocking portion 25 is inserted from the attachment hole H of the panelmember P and positioned such that a lower portion of the attachment holeH of the panel member P in the drawings is sandwiched between theleading end portion 25B and the truncated cone-shaped portion 32.

Next, when the grommet 1 is pushed into the attachment hole H using thepoint of application of force that is indicated by arrow A in FIG. 2,the insertion wall portion 21 is rotated about the point of abutmentbetween the leading end portion 25B of the first locking portion 25 andthe panel member P, the point of abutment serving as the fulcrum, and isfitted into the attachment hole H.

Then, when the grommet 1 continues to be pushed into the attachment holeH, as shown in FIG. 1, the locking claw 26 a on the opposite side to thefirst locking portion 25 is locked on the opening edge portion of theattachment hole H, and the grommet 1 is fitted into the attachment holeH.

As described above, according to the present embodiment, in the grommet1, the leading end portion 25B of the first locking portion 25 islocated on the outward side with respect to the radial direction of theannular seal lip portion 33, and thus the visibility of the firstlocking portion 25 at the start of attachment of the grommet 1 can beimproved. Moreover, during attachment of the grommet 1 to the panelmember P, the first locking portion 25 is first inserted into theattachment hole H, the grommet 1 is rotated using the point of abutmentbetween the leading end portion 25B of that first locking portion 25 andthe panel member P as the fulcrum of rotation, and the second lockingportion 26 disposed on the opposite side to the first locking portion 25is locked on the panel member P. The grommet 1 can be attached to thepanel member P in this manner.

More specifically, the insertion wall portion 21 is fitted into theattachment hole H from the lower end of the insertion wall portion 21 inthe drawings, and then upper portions of the insertion wall portion 21in the drawings are gradually fitted into the attachment hole H. At thistime, in the present embodiment, the portion that is located radiallyoutward of the annular seal lip portion 33, that is, the region ofabutment between the leading end portion 25B of the first lockingportion 25 and the panel member P is used as the fulcrum of rotation ofthe grommet 1. Therefore, the point of application of force, which isindicated by arrow A in FIG. 2, can be set at a position that isfarthest from the fulcrum of rotation. Thus, according to the principleof levers, only a small pushing force is required to be exerted on thepoint of application of force.

Thus, both an improvement of the visibility of the first locking portion25 and the second locking portions 26 at the start of attachment of thegrommet 1 and a reduction of an insertion force that is required duringthe attaching operation can be achieved, so that excellent ease ofattachment can be achieved.

Moreover, when compared with a pushing force that is required in thecase where a grommet having a configuration equivalent to that of aconventional grommet is prepared by removing the first locking portion25 and attached linearly to the attachment hole, the grommet 1 of thepresent embodiment can be fitted into the attachment hole H by 15 to 20%of that pushing force.

Moreover, since the first locking portion 25 and the second lockingportions 26 are formed integrally with the insertion wall portion 21,the manufacturing cost of the grommet 1 can be reduced. Also, thestrength of the grommet 1 can be increased.

Moreover, the first locking portion 25, the second locking portions 26,and the like, which are integral with the insertion wall portion 21, andthe flange portion 22 can be composed of a hard material. Moreover, whenthe grommet 1 is mounted onto the attachment hole H, and the annularseal lip portion 33 abuts against the panel member P on the outside ofthe attachment hole H, the annular seal lip portion 33 composed of anelastic material that is softer than the insertion wall portion 21 canbe supported by the flange portion 22, and thus the sealability can besecured.

Incidentally, although the attachment hole H of the panel member P ofthe foregoing embodiment is shown as a simple opening that is formed byfor example, punching or the like of a sheet metal, as shown in FIG. 4,for example, the present invention is also applicable to a panel memberP′ in which the opening circumferential edge portion of the attachmenthole H is bent so as to have a certain thickness.

As described above, a grommet according to the present invention has theeffect of being capable of providing a grommet that can achieve both animprovement of the visibility of a locking portion at the start ofattachment of that grommet and a reduction of the insertion force thatis required during the attaching operation, and that thus has excellentease of attachment, and is useful for all grommets including a grommetthat, when mounted onto an attachment hole that is formed in a vehiclebody panel, protects a wire harness or the like inserted into theattachment hole and seals the attachment hole in a water-tight manner,such as a grommet for a wire harness that is routed in an environment inwhich its path meanders, for example.

LIST OF REFERENCE NUMERALS

P Panel member

H Attachment hole

21 Insertion wall portion

22 Flange portion

25 First locking portion

25A Base end portion

25B Leading end portion

26 Second locking portion

32 Truncated cone-shaped portion

32 a Attachment surface

33 Annular seal lip portion

1. A grommet comprising: a tubular grommet main body that has atruncated cone-shaped portion having a larger diameter than anattachment hole of a panel member and that has an annular seal lipportion on an attachment surface side of the truncated cone-shapedportion that opposes the panel member; a first locking portion thatprotrudes from the attachment surface of the truncated cone-shapedportion on an inward side with respect to a radial direction of theannular seal lip portion, and that is configured to be locked on thepanel member through the attachment hole; and a second locking portionthat protrudes from the attachment surface of the truncated cone-shapedportion on the inward side with respect to the radial direction of theannular seal lip portion, and that is configured to be locked on thepanel member through the attachment hole when the annular seal lipportion comes into contact with the panel member, wherein the firstlocking portion has a base end portion that protrudes from theattachment surface of the truncated cone-shaped portion on the inwardside with respect to the radial direction of the annular seal lipportion, and a leading end portion that protrudes from the base endportion toward the truncated cone-shaped portion on an outward side withrespect to the radial direction of the annular seal lip portion, and thesecond locking portion is disposed on a side that is opposite to thefirst locking portion with respect to at least the center of thetruncated cone-shaped portion.
 2. The grommet according to claim 1,wherein the grommet main body has a tubular insertion wall portion thatis configured to be inserted into the attachment hole of the panelmember, and the first locking portion and the second locking portion areformed integrally with the insertion wall portion.
 3. The grommetaccording to claim 2, wherein the insertion wall portion is composed ofa hard material having a flange portion that is embedded in thetruncated cone-shaped portion, and at least the annular seal lip portionis composed of an elastic material that is softer than the hardmaterial.